(function() {
  var Nr = 10;
  // convert two-dimensional indicies to one-dim array indices
  var I00 = 0;
  var I01 = 1;
  var I02 = 2;
  var I03 = 3;
  var I10 = 4;
  var I11 = 5;
  var I12 = 6;
  var I13 = 7;
  var I20 = 8;
  var I21 = 9;
  var I22 = 10;
  var I23 = 11;
  var I30 = 12;
  var I31 = 13;
  var I32 = 14;
  var I33 = 15;

  // S-Box substitution table
  var S_enc = new Array(
    0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5,
    0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
    0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0,
    0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
    0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc,
    0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
    0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a,
    0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
    0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0,
    0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
    0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b,
    0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
    0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85,
    0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
    0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5,
    0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
    0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17,
    0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
    0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88,
    0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
    0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c,
    0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
    0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9,
    0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
    0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6,
    0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
    0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e,
    0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
    0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94,
    0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
    0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68,
    0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16);

  // inverse S-Box for decryptions
  var S_dec = new Array(
    0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38,
    0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
    0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87,
    0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
    0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d,
    0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
    0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2,
    0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
    0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16,
    0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
    0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda,
    0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
    0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a,
    0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
    0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02,
    0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
    0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea,
    0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
    0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85,
    0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
    0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89,
    0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
    0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20,
    0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
    0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31,
    0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
    0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d,
    0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
    0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0,
    0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
    0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26,
    0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d);

  function cvt_hex8(val) {
    var vh = (val >>> 4) & 0x0f;
    return vh.toString(16) + (val & 0x0f).toString(16);
  }

  function cvt_byte(str) {
    // get the first hex digit
    var val1 = str.charCodeAt(0);
    // do some error checking
    if (val1 >= 48 && val1 <= 57) {
      // have a valid digit 0-9
      val1 -= 48;
    } else if (val1 >= 65 && val1 <= 70) {
      // have a valid digit A-F
      val1 -= 55;
    } else if (val1 >= 97 && val1 <= 102) {
      // have a valid digit A-F
      val1 -= 87;
    } else {
      // not 0-9 or A-F, complain
      console.log(str.charAt(1) + " is not a valid hex digit");
      return -1;
    }
    // get the second hex digit
    var val2 = str.charCodeAt(1);
    // do some error checking
    if (val2 >= 48 && val2 <= 57) {
      // have a valid digit 0-9
      val2 -= 48;
    } else if (val2 >= 65 && val2 <= 70) {
      // have a valid digit A-F
      val2 -= 55;
    } else if (val2 >= 97 && val2 <= 102) {
      // have a valid digit A-F
      val2 -= 87;
    } else {
      // not 0-9 or A-F, complain
      console.log(str.charAt(2) + " is not a valid hex digit");
      return -1;
    }
    // all is ok, return the value
    return val1 * 16 + val2;
  }

  // conversion function for non-constant subscripts
  // assume subscript range 0..3
  function I(x, y) {
    return (x * 4) + y;
  }

  // remove spaces from input
  function remove_spaces(instr) {
    var i;
    var outstr = "";
    for (i = 0; i < instr.length; i++) {
      if (instr.charAt(i) != " ")
        // not a space, include it
        outstr += instr.charAt(i);
    }
    return outstr;
  }

  // get the message to encrypt/decrypt or the key
  // return as a 16-byte array
  function get_value(str, isASCII) {
    var dbyte = new Array(16);
    var i;
    var val; // one hex digit
    if (isASCII) {
      // check length of data
      if (str.length > 16) {
        console.log("is too long, using the first 16 ASCII characters");
      }
      // have ASCII data
      // 16 characters?
      if (str.length >= 16) {
        // 16 or more characters
        for (i = 0; i < 16; i++) {
          dbyte[i] = str.charCodeAt(i);
        }
      } else {
        // less than 16 characters - fill with NULLs
        for (i = 0; i < str.length; i++) {
          dbyte[i] = str.charCodeAt(i);
        }
        for (i = str.length; i < 16; i++) {
          dbyte[i] = 0;
        }
      }
    } else {
      // have hex data - remove any spaces they used, then convert
      //str = remove_spaces(str);
      // check length of data
      if (str.length != 32) {
        //console.log("\tget_value:\tstr = " + str + "\tisASCII = " + isASCII); //isASCII = false
        console.log("length wrong: Is " + str.length + " hex digits, but must be 128 bits (32 hex digits)");
        dbyte[0] = -1;
        return dbyte;
      }
      for (i = 0; i < 16; i++) {
        // isolate and convert this substring
        dbyte[i] = cvt_byte(str.substr(i * 2, 2));
        if (dbyte[i] < 0) {
          // have an error
          dbyte[0] = -1;
          return dbyte;
        }
      }
    }
    // return successful conversion
    return dbyte;
  }
  //do the AES GF(2**8) multiplication
  // do this by the shift-and-"add" approach
  function aes_mul(a, b) {
    var res = 0;
    while (a > 0) {
      if ((a & 1) != 0)
        res = res ^ b; // "add" to the result
      a >>>= 1; // shift a to get next higher-order bit
      b <<= 1; // shift multiplier also
    }
    // now reduce it modulo x**8 + x**4 + x**3 + x + 1
    var hbit = 0x10000; // bit to test if we need to take action
    var modulus = 0x11b00; // modulus - XOR by this to change value
    while (hbit >= 0x100) {
      if ((res & hbit) != 0) {
        res ^= modulus; // XOR with the modulus
      }
      // prepare for the next loop
      hbit >>= 1;
      modulus >>= 1;
    }
    return res;
  }

  // apply the S-box substitution to the key expansion
  function SubWord(word_ary) {
    var i;
    for (i = 0; i < 16; i++) {
      word_ary[i] = S_enc[word_ary[i]];
    }
    return word_ary;
  }

  // rotate the bytes in a word
  function RotWord(word_ary) {
    return new Array(word_ary[1], word_ary[2], word_ary[3], word_ary[0]);
  }

  // calculate the first item Rcon[i] = { x^(i-1), 0, 0, 0 }
  // note we only return the first item
  function Rcon(exp) {
    var val = 2;
    var result = 1;

    // remember to calculate x^(exp-1)
    exp--;

    // process the exponent using normal shift and multiply
    while (exp > 0) {
      if ((exp & 1) != 0)
        result = aes_mul(result, val);

      // square the value
      val = aes_mul(val, val);

      // move to the next bit
      exp >>= 1;
    }

    return result;
  }
  // round key generation
  // return a byte array with the expanded key information
  function key_expand(key) {
    var temp = new Array(4);
    var i, j;
    var w = new Array(4 * (Nr + 1));

    // copy initial key stuff
    for (i = 0; i < 16; i++) {
      w[i] = key[i];
    }

    // generate rest of key schedule using 32-bit words
    i = 4;
    while (i < 4 * (Nr + 1)) // blocksize * ( rounds + 1 )
    {
      // copy word W[i-1] to temp
      for (j = 0; j < 4; j++)
        temp[j] = w[(i - 1) * 4 + j];

      if (i % 4 == 0) {
        // temp = SubWord(RotWord(temp)) ^ Rcon[i/4];
        temp = RotWord(temp);
        temp = SubWord(temp);
        temp[0] ^= Rcon(i >>> 2);
      }

      // word = word ^ temp
      for (j = 0; j < 4; j++)
        w[i * 4 + j] = w[(i - 4) * 4 + j] ^ temp[j];

      i++;
    }

    return w;
  }

  // do S-Box substitution
  function SubBytes(state, Sbox) {
    var i;

    for (i = 0; i < 16; i++)
      state[i] = Sbox[state[i]];

    return state;
  }

  // shift each row as appropriate
  function ShiftRows(state) {
    var t0, t1, t2, t3;

    // top row (row 0) isn't shifted

    // next row (row 1) rotated left 1 place
    t0 = state[I10];
    t1 = state[I11];
    t2 = state[I12];
    t3 = state[I13];
    state[I10] = t1;
    state[I11] = t2;
    state[I12] = t3;
    state[I13] = t0;

    // next row (row 2) rotated left 2 places
    t0 = state[I20];
    t1 = state[I21];
    t2 = state[I22];
    t3 = state[I23];
    state[I20] = t2;
    state[I21] = t3;
    state[I22] = t0;
    state[I23] = t1;

    // bottom row (row 3) rotated left 3 places
    t0 = state[I30];
    t1 = state[I31];
    t2 = state[I32];
    t3 = state[I33];
    state[I30] = t3;
    state[I31] = t0;
    state[I32] = t1;
    state[I33] = t2;

    return state;
  }

  // inverset shift each row as appropriate
  function InvShiftRows(state) {
    var t0, t1, t2, t3;

    // top row (row 0) isn't shifted

    // next row (row 1) rotated left 1 place
    t0 = state[I10];
    t1 = state[I11];
    t2 = state[I12];
    t3 = state[I13];
    state[I10] = t3;
    state[I11] = t0;
    state[I12] = t1;
    state[I13] = t2;

    // next row (row 2) rotated left 2 places
    t0 = state[I20];
    t1 = state[I21];
    t2 = state[I22];
    t3 = state[I23];
    state[I20] = t2;
    state[I21] = t3;
    state[I22] = t0;
    state[I23] = t1;

    // bottom row (row 3) rotated left 3 places
    t0 = state[I30];
    t1 = state[I31];
    t2 = state[I32];
    t3 = state[I33];
    state[I30] = t1;
    state[I31] = t2;
    state[I32] = t3;
    state[I33] = t0;

    return state;
  }

  // process column info
  function MixColumns(state) {
    var col;
    var c0, c1, c2, c3;

    for (col = 0; col < 4; col++) {
      c0 = state[I(0, col)];
      c1 = state[I(1, col)];
      c2 = state[I(2, col)];
      c3 = state[I(3, col)];

      // do mixing, and put back into array
      state[I(0, col)] = aes_mul(2, c0) ^ aes_mul(3, c1) ^ c2 ^ c3;
      state[I(1, col)] = c0 ^ aes_mul(2, c1) ^ aes_mul(3, c2) ^ c3;
      state[I(2, col)] = c0 ^ c1 ^ aes_mul(2, c2) ^ aes_mul(3, c3);
      state[I(3, col)] = aes_mul(3, c0) ^ c1 ^ c2 ^ aes_mul(2, c3);
    }

    return state;
  }

  // inverse process column info
  function InvMixColumns(state) {
    var col;
    var c0, c1, c2, c3;

    for (col = 0; col < 4; col++) {
      c0 = state[I(0, col)];
      c1 = state[I(1, col)];
      c2 = state[I(2, col)];
      c3 = state[I(3, col)];

      // do inverse mixing, and put back into array
      state[I(0, col)] = aes_mul(0x0e, c0) ^ aes_mul(0x0b, c1) ^
        aes_mul(0x0d, c2) ^ aes_mul(0x09, c3);
      state[I(1, col)] = aes_mul(0x09, c0) ^ aes_mul(0x0e, c1) ^
        aes_mul(0x0b, c2) ^ aes_mul(0x0d, c3);
      state[I(2, col)] = aes_mul(0x0d, c0) ^ aes_mul(0x09, c1) ^
        aes_mul(0x0e, c2) ^ aes_mul(0x0b, c3);
      state[I(3, col)] = aes_mul(0x0b, c0) ^ aes_mul(0x0d, c1) ^
        aes_mul(0x09, c2) ^ aes_mul(0x0e, c3);
    }

    return state;
  }

  // insert subkey information
  function AddRoundKey(state, w, base) {
    var col;

    for (col = 0; col < 4; col++) {
      state[I(0, col)] ^= w[base + col * 4];
      state[I(1, col)] ^= w[base + col * 4 + 1];
      state[I(2, col)] ^= w[base + col * 4 + 2];
      state[I(3, col)] ^= w[base + col * 4 + 3];
    }

    return state;
  }

  // return a transposed array
  function transpose(msg) {
    var row, col;
    var state = new Array(16);

    for (row = 0; row < 4; row++)
      for (col = 0; col < 4; col++)
        state[I(row, col)] = msg[I(col, row)];

    return state;
  }

  // final AES state
  var AES_output = new Array(16);

  // format AES output
  // -- uses the global array DES_output
  function format_AES_output(bASCII) {
    var i;
    var bits;
    var str = "";

    // what type of data do we have to work with?
    if (bASCII) {
      // convert each set of bits back to ASCII
      for (i = 0; i < 16; i++)
        str += String.fromCharCode(AES_output[i]);
    } else {
      // output hexdecimal data (insert spaces)
      str = cvt_hex8(AES_output[0]);
      for (i = 1; i < 16; i++) {
        str += "" + cvt_hex8(AES_output[i]);
      }
    }
    return str;
  }

  // do encrytion
  function aes_encrypt(str, key, bASCII) {
    //console.log("  aes_encrypt:\tstr = " + str + "\tkey = " + key + "\t bASCII = " + bASCII);
    var w = new Array(4 * (Nr + 1)); // subkey information
    var state = new Array(16); // working state
    var round;

    //accumulated_output_info = "";

    // get the message from the user
    // also check if it is ASCII or hex
    var msg = get_value(str, bASCII);

    // problems??
    if (msg[0] < 0) {
      return;
    }

    // get the key from the user
    var key = get_value(key, false);
    // problems??
    if (key[0] < 0) {
      return;
    }

    // expand the key
    w = key_expand(key);

    // initial state = message in columns (transposed from what we input)
    state = transpose(msg);

    // display the round key - Transpose due to the way it is stored/used
    state = AddRoundKey(state, w, 0);

    for (round = 1; round < Nr; round++) {
      state = SubBytes(state, S_enc);
      state = ShiftRows(state);
      state = MixColumns(state);
      // display the round key - Transpose due to the way it is stored/used
      // note here the spec uses 32-bit words, we are using bytes, so an extra *4
      state = AddRoundKey(state, w, round * 4 * 4);
    }

    SubBytes(state, S_enc);
    ShiftRows(state);
    AddRoundKey(state, w, Nr * 4 * 4);

    // process output
    AES_output = transpose(state);
    var szOutput = format_AES_output(!bASCII);
    return szOutput;
  }

  // do decryption
  function aes_decrypt(str, key, bASCII) {
    //console.log("  aes_decrypt:\tstr = " + str + "\tkey = " + key + "\tbASCII = " + bASCII);
    var w = new Array(4 * (Nr + 1)); // subkey information
    var state = new Array(16); // working state
    var round;

    //accumulated_output_info = "";

    // get the message from the user
    // also check if it is ASCII or hex
    var msg = get_value(str, bASCII);

    // problems??
    if (msg[0] < 0) {
      return;
    }

    // get the key from the user
    var key = get_value(key, false);
    // problems??
    if (key[0] < 0) {
      return;
    }

    // expand the key
    w = key_expand(key);

    // initial state = message
    state = transpose(msg);
    // display the round key - Transpose due to the way it is stored/used
    state = AddRoundKey(state, w, Nr * 4 * 4);

    for (round = Nr - 1; round >= 1; round--) {
      state = InvShiftRows(state);
      state = SubBytes(state, S_dec);
      // display the round key - Transpose due to the way it is stored/used
      // note here the spec uses 32-bit words, we are using bytes, so an extra *4
      state = AddRoundKey(state, w, round * 4 * 4);
      state = InvMixColumns(state);
    }

    InvShiftRows(state);
    SubBytes(state, S_dec);
    AddRoundKey(state, w, 0);

    // process output
    AES_output = transpose(state);
    var szOutput = format_AES_output(!bASCII);
    return szOutput;
  }
  window.aes_encrypt = aes_encrypt;
  window.aes_decrypt = aes_decrypt;
  window.console = window.console || {
    log: function() {}
  };
}());